Unpleasant odors/tastes due to natural deterioration: Food off-flavors

Human-food interactions impact food acceptance and thereby the nutritional status of individuals. It is often said that even a hungry person would not eat if the sensory aspect of the food is offensive.

Flavor is one of the most important sensory qualities of a food. The flavor of a food is determined by a complex mix of taste, aroma, chemical response and texture.

Identification of the compounds causing an off-flavor in food and accurate quantification is critical in assessing the potential safety risks of a product or ingredient. Even when the tainting compounds are not at a level that would cause a safety concern, off flavors can have a significant impact on the quality and consumers' acceptability of products.

Off-flavors are widely defined as unpleasant odors or tastes resulting from the natural deterioration of a food. Off-flavors can be triggered by the involatiles detected by taste, but the main chemicals involved are the volatiles involved in odor response.

It is an atypical odor or taste may be due to incidental contamination of the food from environmental sources (e.g., airborne‐, waterborne‐, or packaging‐related chemicals) or may arise in the food itself (e.g., lipid oxidation, non-enzymatic browning or enzymatic action).

The oxidation can be enzymatic or nonenzymatic. Furthermore, off-flavors can be formed by the effect of heat on sugars and amino acids, such as Maillard reactions, by thermal degradation of phenolic acids, by oxidative and thermal degradation of carotenoids, and by thermal degradation of thiamine, or they can be derived as contaminants after solvent extraction.
Unpleasant odors/tastes due to natural deterioration: Food off-flavors